Might be just me, but if this is the script, where are you setting the variables used in the query?
//-query the database table
$sql="SELECT Title, Post, Date
WHERE Title LIKE '%" . $Title . "%'
OR Post LIKE '%" . $Post . "%' OR Date LIKE '%" . $Date ."%'";
Fair enough that your looking for $Title, $Post and $Date, but I can't seem to find them being filled somewhere...
your $sql statement before it's queried, and add an
to your mysql_query()